Abstract: EMPLOYEE #1 WAS ATTEMPTING TO REMOVE A HYDRAULIC LINE SO THAT HE COULD USE IT AS A SAMPLE IN MAKING ANOTHER ONE. HE USED A HAND OPERATED PUMP ON THE DRAWBAR TO RAISE THE DUMP BOX ON THE CEMENT DELIVERY TRAILER TO GAIN ACCESS TO THE HYDRAULIC LINE AT ITS ATTACH POINT (AT THE LIFTING CYLINDER). HE ENTERED THE MACHINE BETWEEN THE TWO AXLES ON THE RIGHT SIDE OF THE DUMP TRAILER. HIS UPPER CHEST WAS LOCATED BETWEEN THE RAISED BOX AND THE STEEL FRAME OF THE DUMP BOX. HE USED AN ADJUSTABLE WRENCH TO DISCONNECT THE HYDRAULIC LINE FROM THE CYLINDER. WHEN IT WAS FREE, THE HYDRAULIC FLUID WAS EXPELLED FROM THE EXTENDED CYLINDER BY THE WEIGHT OF THE BOX. THE BOX THEN SETTLED DOWN ONTO HIS BACK, CAUSING HIS CHEST TO BE CONSTRICTED BETWEEN THE BOX AND STEEL FRAME. DEATH WAS DUE TO ASPHYXIA, WITH NO FRACTURES OR INTERNAL ORGAN DAMAGE. THE TRAILER'S DUMP BOX WAS APPROXIMATELY 50 FEET WIDE AND 94 FEET LONG, OF 1/8 INCH STEEL CONSTRUCTION. IT HAD A CAPACITY OF 1.25 CUBIC YARDS OF CEMENT. THE INTERIOR OF THE BOX HAD A 1/16 TO 1/8 INCH BUILDUP OF HARDENED CEMENT, AND 3 TO 4 CUBIC FEET OF ICE LOCATED IN THE FRONT HALF OF THE BOX. THERE WERE NO WITNESSES TO THE ACCIDENT. EMPLOYEE #1 WAS NOT EXTRICATED FOR APPROXIMATELY TWO HOURS.